Math problem

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Tanya Tanya
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Math problem

Six years ago James was five times as old as Cindy. Twelve years from now James will be twice Cindy age. What is the average age of James and Cindy two years from now?
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Re: Math problem

x = Cindy's age six years ago
5x = James' age 6 years ago   ← he was five times Cindy

x + 18 = Cindy's age in 12 years   ← she was x, six years ago
5x + 18 = James' age in 12 years   ← he was 5x, six years ago

5x + 18 = 2(x + 18)   ← twelve years from now, James will be twice Cindy
5x + 18 = 2x + 36   ← distributive property
3x = 18   ← subtracted 2x and 18
x = 6   ← divided by 3
5x = 30   ← substituted

Cindy was 6, six years ago.....she is 12 now
James was 30, six years ago....he is 36 now

Cindy will be 12 in two years
James will be 38 in 2 years

Their average in 2 years will be:
38 + 12
---------
     2

=  25

- Proof